using System;

using System.Collections;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

public interface IObserver

    {

        void update(float temp, float humid, float press);

    }

public interface ISubject

{

    void registerObserver(IObserver ob);

    void removeObserver(IObserver ob);

    void notifyObservers();

}

public interface IDisplayElement

{

    void display();

}

public class WeatherData:ISubject

{

    private ArrayList observers;

    private float temperature;

    private float humidity;

    private float pressure;

​

    public WeatherData()

    {

        observers = new ArrayList();    

    }

​

    public void registerObserver(IObserver ob)

    {

        observers.Add(ob);

    }

​

    public void removeObserver(IObserver ob)

    {

        int i = observers.IndexOf(ob);

        if(i>0)

        {

            observers.Remove(i);    

        }

    }

​

    public void notifyObservers()

    {

        for(int i=0; i< observers.Count; i++)

        {

            IObserver observer = (IObserver)observers[i];

            observer.update(temperature, humidity, pressure);

        }

    }

​

    public void measurementsChanged()

    {

        notifyObservers();

    }

    public void setMeasurements(float temperature, float humidity, float pressure)

    {

        this.temperature = temperature;

        this.humidity = humidity;

        this.pressure = pressure;

        measurementsChanged();

    }

}

​

public class CurrentConditionsDisplay: IObserver, IDisplayElement

{

    private float temperature;

    private float humidity;

    private ISubject weatherData;

    public CurrentConditionsDisplay(ISubject weatherData)

    {

        this.weatherData = weatherData;

        weatherData.registerObserver(this);

    }

    public void update(float temperature, float humidity, float pressure)

    {

        this.temperature = temperature;

        this.humidity = humidity;

        display();

    }

    public void display()

    {

        Console.WriteLine("Current conditions: "+ temperature+"F degress and "+humidity+"% humidity");

    }

}